Fuel cell arrangements with at least one bipolar plate layer and at least one electrolyte membrane typically form a fuel cell stack of several fuel cells connected in series, or a part of such a fuel cell stack. Usually a fuel cell stack is manufactured by way of a repetitive joining together of bipolar plates and electrolyte membranes in an alternating sequence, wherein sealing layers may be additionally provided. Multi-layered arrangements which apart from an electrolyte membrane—for example a polymer electrolyte membrane—in the restricted context of the word, may also comprise catalyser layers, electrodes and/or gas diffusion layers which bear on this, are also to be indicated as electrolyte membranes in the present document (such an arrangement which comprises at least one electrolyte membrane is also called an membrane electrode assembly and in particular is occasionally abbreviated as MEA hereinafter). The bipolar plates which are arranged in a fuel cell stack between adjacent electrolyte membranes serve for the creation of an electrical contact between adjacent fuel cells, for the transport of incoming and outgoing reactants or reaction products and typically also for the discharge of reaction heat, for example with the help of coolant channels integrated into the bipolar plates, as well as for sealing the adjacent fuel cells or electrolyte membranes in their edge regions and the active surface. {PRIVATE}
Since electrolyte membranes are mostly fragile and supple, they are difficult to handle on manufacture of a fuel cell arrangement or a fuel cell stack. Difficulties in particular result with an exact positioning of an electrolyte membrane on a bipolar plate which was previously assembled on the stack, and thus related to this, with a sealing of a fuel cell arrangement between a bipolar plate and the electrolyte membrane adjacent thereon. On account of the difficulty of positioning an electrolyte membrane precisely on the bordering bipolar plate, an assembly of a conventional fuel cell arrangement with several fuel cells is furthermore very complicated with regard to automation, which is disadvantageous with regard to mass manufacture.
Typically, fuel cell arrangements of the known type according to the state of the art are therefore manufactured by way of layering bipolar plates and electrolyte membranes onto one another in an alternating sequence, wherein a fuel cell stack which thus arises may be held together for example by way of a mutual clamping of two end plates. Such a manufacturing method entails the disadvantages of the difficult handling of supple electrolyte membranes on assembly of a fuel cell stack and of the likewise difficult realisation of adequately good sealing between adjacent layers.
According to the state of the art, in the case of graphitic bipolar plates, it is likewise known by way of using reactively curing adhesives, cross-linking thermally or under the effect of moisture, to bond bordering electrolyte membranes onto the bipolar plate or to bond these between two bipolar plates. Although a good sealing is achieved with this, difficulties however arise by way of the fact that a cross-linking of the applied adhesive must be externally induced, typically by way of a thermal treatment. With this, damage to the temperature-sensitive electrolyte membranes which for example may contract, dry out or tear on account of this, is very difficult to avoid. Adhesives curing under the effect of moisture or by reactive gases (carbon dioxide for example) also do not simplify the manufacture, since the bonding layer between an electrolyte membrane and a bordering bipolar plate is situated at a difficultly accessible location, and therefore may be subjected to moisture only with great difficultly and/or not in adequately complete and homogenous manner. A manufacture of a fuel cell arrangement with the use of such adhesives furthermore demands an enormous amount of expense with regard to time, since with this, the adjacent bipolar plates and electrolyte membranes must be held under compressive stress for a relatively long period of time. An assembly of a fuel cell stack has been shown to be even more cumbersome. In particular, an automated assembly of fuel cell stacks is therefore at least too time-consuming with fuel cell arrangements according to the state of the art—certainly with large production numbers which are industrially relevant.